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| United States Patent |
5,066,766
|
|
Jackson, Jr.
, et al.
|
November 19, 1991
|
Process for the preparation of poly(ester-carbonates)
Abstract
Disclosed is a process for the preparation of poly(ester-carbonates)
wherein (1) an aromatic diol, (2) methyl phenyl carbonate and (3) an alkyl
carboxylate ester component selected from an aromatic dicarboxylate ester,
a hydroxy aromatic carboxylate ester or a mixture thereof are contacted in
the presence of a transesterification/polycondensation catalyst under
transesterification/polycondensation conditions of pressure and
temperature.
| Inventors:
|
Jackson, Jr.; Winston J. (Kingsport, TN);
Darnell; William R. (Weber City, VA)
|
| Assignee:
|
Eastman Kodak Company (Rochester, NY)
|
| Appl. No.:
|
508756 |
| Filed:
|
April 13, 1990 |
| Current U.S. Class: |
528/190; 528/176; 528/179; 528/180; 528/181; 528/193; 528/194; 528/271; 528/272 |
| Intern'l Class: |
C08G 063/02; C08G 063/00; C08G 067/00; C08G 069/00 |
| Field of Search: |
528/176,179,180,181,190,193,194,271,272
|
References Cited
U.S. Patent Documents
| 4107143 | Aug., 1978 | Inata et al. | 528/176.
|
| 4398018 | Aug., 1983 | Akkapeddi et al. | 528/191.
|
| 4435561 | Mar., 1984 | Lai et al. | 528/193.
|
| 4612362 | Sep., 1986 | Lai et al. | 528/190.
|
| Foreign Patent Documents |
| 303931 | Feb., 1989 | EP.
| |
| 303935 | Feb., 1989 | EP.
| |
Primary Examiner: Kight, III; John
Assistant Examiner: Mosley; Terressa M.
Attorney, Agent or Firm: Thomsen; J. Frederick, Heath, Jr.; William P.
Claims
We claim:
1. Process for the preparation of a poly(ester-carbonate) which comprises
contacting (1) an aromatic diol, (2) methyl phenyl carbonate and (3) a
carboxylate alkyl ester component selected from an aromatic dicarboxylate
ester, a hydroxy aromatic carboxylate ester or a mixture thereof in the
presence of a transesterification/polycondensation catalyst under
transesterification/polycondensation conditions of pressure and
temperature.
2. Process according to claim 1 wherein the aromatic diol is a benzenediol,
a naphthalenediol, a biphenyldiol, a bis(hydroxyphenyl)alkane or a mixture
thereof and the carboxylate ester component is a benzenedicarboxylate
ester, a naphthalenedicarboxylate ester, a hydroxybenzoate ester or a
mixture thereof and at least 1 mole of methyl phenyl carbonate is used per
equivalent of aromatic hydroxy group of the aromatic diol and, if present,
the hydroxybenzoate ester reactants.
3. Process according to claim 1 wherein the process is carried out at
temperatures of about 180.degree. to 380.degree. C. and pressures of about
ambient to 0.1 torr.
4. Process for the melt phase preparation of a poly(ester-carbonate) which
comprises contacting (1) an aromatic diol selected from a benzenediol, a
naphthalenediol, a biphenyldiol, a bis(hydroxyphenyl)alkane or a mixture
thereof, (2) methyl phenyl carbonate and (3) an alkyl carboxylate ester
component selected from a benzenedicarboxylate ester, a
naphthalenedicarboxylate ester, a hydroxybenzoate ester or a mixture
thereof, in the presence of a transesterification/polycondensation
catalyst, wherein (i) at least 1 mole of methyl phenyl carbonate is used
per equivalent of aromatic hydroxy group of the aromatic diol and, if
present, the hydroxybenzoate ester reactants and (ii) the process is
performed in a first stage at temperatures of about 180.degree. to
250.degree. C. at about ambient pressure and in a second stage at
temperatures of about 320.degree. to 350.degree. C. at pressures of
ambient to 0.1 torr.
5. A process according to claim 4 which comprises contacting (1)
2,2-bis(4-hydroxyphenyl)propane, (2) methyl phenyl carbonate and (3)
dimethyl 1,3-benzenedicarboxylate, dimethyl 1,4-benzenedicarboxylate, or a
mixture thereof.
6. A process according to claim 4 which comprises contacting (1)
1,4-benzenediol, (2) methyl phenyl carbonate and (3) dimethyl
1,3-benzenedicarboxylate, dimethyl 1,4-benzenedicarboxylate, or a mixture
thereof.
Description
This invention pertains to a novel process for the preparation of
poly(ester-carbonates) from aromatic diols and at least one aromatic
dicarboxylate diester and/or at least one hydroxyaromatic carboxylate
ester. More specifically, this invention pertains to the preparation of
poly(ester-carbonates) by the reaction of such aromatic diols and esters
with methyl phenyl carbonate in the presence of a
transesterification/polycondensation catalyst or catalyst system.
European Patent Application 303,931 discloses a process for preparing
thermotropic, wholly-aromatic polyesters and poly(ester-carbonates) by
esterifying an optionally-substituted hydroxybenzoic acid and an aromatic
dicarboxylic acid with a diaryl carbonate and subsequently
transesterifying the resulting diaryl esters with an aromatic diol,
optionally in the presence of a catalyst consisting of heterocyclic
compounds containing 1 to 3 nitrogen atoms. A similar process is described
in European Patent Application 303,935 wherein the aryl esters formed in
the first stage of the process are transesterified with an aromatic diol,
additional diaryl carbonate, and, optionally, a chain terminator.
U.S. Pat. No. 4,107,143 discloses the preparation of thermotropic,
wholly-aromatic poly(ester-carbonates) consisting essentially of the
residues of hydroxybenzoic acid, hydroquinone, carbonic acid and,
depending on the particular poly(ester carbonate), an aromatic
dicarboxylic acid. The hydroxybenzoic acid residues and aromatic
dicarboxylic acid residues are derived only from the acids or the aryl
esters of the acids and the carbonic acid residues are obtained
exclusively from a diaryl carbonate.
The process provided by the present invention does not utilize a diaryl
carbonate nor does the process require the use of nitrogen-containing
heterocyclic compounds. The use of methyl phenyl carbonate in accordance
with our novel process is advantageous since it is potentially more
economical than diaryl carbonates due to the development of processes
whereby methyl phenyl carbonate may be produce from phenol, methanol,
oxygen and carbon monoxide, e.g., the process described in Chemical &
Engineering News, Nov. 2, 1987. Furthermore, the use of methyl phenyl
carbonate rather than diphenyl carbonate in the manufacture of
poly(ester-carbonates) results in the liberation of substantially less
phenol which is a toxic, hazardous-to-handle material. Methyl phenyl
carbonate also is advantageous since it is a liquid under ambient
conditions.
The present invention provides a process for the preparation of
poly(ester-carbonates) wherein (1) an aromatic diol, (2) methyl phenyl
carbonate and (3) an alkyl carboxylate ester component selected from an
aromatic dicarboxylate ester, a hydroxy aromatic carboxylate ester or a
mixture thereof are contacted in the presence of a
transesterification/polycondensation catalyst under
transesterification/polycondensation conditions of pressure and
temperature. In the practice of the process, a mixture of the above
described is heated, typically at ambient or autogenous pressure, to
effect reaction of the methyl phenyl carbonate with the aromatic hydroxyl
groups, i.e., the hydroxyl groups bonded to a ring carbon atom of an
aromatic ring. The temperature then is increased and the mixture is heated
at the increased temperature, typically under reduced pressure, until the
desired degree of polycondensation has occurred. The polycondensation
product may consist of the final poly(ester-carbonate) or it may be a
prepolymer which may be ground and further polymerized or polycondensed
using conventional solid state polymerization procedures.
The aromatic diols which may be used in the process of the present
invention are comprised of dihydroxy aromatic compounds of 6 to about 18
carbon atoms wherein the hydroxy groups are bonded to a ring carbon atom
of an aromatic ring. Examples of the aromatic diols include the
benzenediols such as 1,4-benzenediol (hydroquinone), 1,3-benzenediol
(resorcinol) and benzene diols substituted with alkyl, halogen, phenyl,
etc.; naphthalenediols such as 2,6-naphthalenediol; biaryldiols such as
4,4'-biphenol; bis(hydroxyphenyl) ethers such as 4,4'-oxydiphenol; and
bis(hydroxyphenyl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane
(bisphenol A). The aromatic diol preferably is a benzenediol or a
bis(hydroxyphenyl)alkane, especially 1,4-benzenediol and
2,2-bis(4-hydroxyphenyl)propane.
The carboxylate ester reactant may be selected from an aromatic
dicarboxylate ester such as a dialkyl ester of an aromatic dicarboxylic
acid, a hydroxy aromatic carboxylate ester such a lower alkyl ester of
hydroxybenzoic or hydroxynaphthalenecarboxylic acid or a mixture thereof.
The alkyl groups may contain up to about 4 carbon atoms although the
methyl ester is particularly preferred. Specific examples of the aromatic
carboxylate ester reactants include dimethyl 1,4-benzenedicarboxylate
(dimethyl terephthalate), dimethyl 1,3-benzenedicarboxylate (dimethyl
isophthalate), dimethyl 2,6-naphthalenedicarboxylate, dimethyl
2,7-naphthalenedicarboxylate, dimethyl 4,4'-biphenyldicarboxylate,
dimethyl 4,4'-oxydibenzoate, methyl 4-hydroxybenzoate, methyl
3-hydroxybenzoate, methyl 6-hydroxy-2-naphthalene-6-carboxylate and the
like.
The ratio of carbonate to ester linkages present in the
poly(ester-carbonates) obtained in accordance with this invention can vary
significantly depending on the mole ratio of carboxylate ester to aromatic
diol used and the particular carboxylate ester employed. The carbonate to
ester ratio normally is in the range of about 15:85 to 95:5, preferably
about 20:80 to 80:20. Thus, when the carboxylate ester reactant consists
of an aromatic dicarboxylate ester, the mole ratio of dicarboxylate ester
to aromatic diol may be about 5:100 to 85:100, preferably about 20:100 to
80:100. When the carboxylate ester reactant consists of a hydroxy aromatic
carboxylate ester, the mole ratio of hydroxy aromatic carboxylate ester to
aromatic diol may be about 5:95 to 85:15, preferably about 20:80 to 80:20.
The particular ratio of reactants employed will depend primarily on the
particular polymer, including the combination of polymer properties,
desired and the particular reactants employed. The poly(ester-carbonates)
prepared in accordance with our invention may be crystalline or amorphous.
The crystalline polymers typically have a melting point of up to about
380.degree. C., preferably below 340.degree. C.
The amount of methyl phenyl carbonate used normally is at least 1 mole per
equivalent of aromatic hydroxyl of the aromatic diol reactant and, if
present, the hydroxy aromatic carboxylate reactant. Preferably, a slight
to moderate excess, e.g., up to about 50 mole percent excess, of methyl
phenyl carbonate is used.
The transesterification/polycondensation catalysts and catalyst systems
useful in the practice of our invention are well-known to those skilled in
the art of condensation polymers. Examples of such catalysts include
titanium, tin, lead and alkaline earth metals, optionally in combination
with antimony and/or germanium. The preferred catalyst is titanium,
provided as a tetraalkyl titanate, e.g., tetraisopropyl titanate (titanium
tetraisopropoxide), or an acyl trialkyl titanate, e.g, acetyl triisopropyl
titanate. The concentration of the catalyst can vary substantially
depending on a number of factors such as the particular catalyst or
catalyst system and/or the transesterification/polycondensation conditions
used. Typically, the concentration of the catalyst, calculated as the
metal, is in the range of about 25 to 500 parts per million (ppm) based on
the theoretical yield of the poly(ester-carbonate) product. Preferably, a
titanium catalyst, especially tetraisopropyl titanate, is used in a
concentration of about 100 to 400 ppm, calculated as [Ti] and based on the
theoretical yield of the poly(ester-carbonate) product.
The transesterification/polycondensation temperatures can vary widely
depending on the melting point of the poly(ester-carbonate) product, the
thermal stability of the poly(ester-carbonate) product and the method used
for the polycondensation stage of the process, i.e., melt-phase or
solid-phase polycondensation. Normally, the process is carried out at
temperatures in the range of about 180.degree. C. up to a maximum of about
380.degree. C., preferably up to a maximum temperature of about
330.degree. to 350.degree. C.
The initial or transesterification segment of the process, wherein the
aromatic hydroxy groups react with methyl phenyl carbonate, may be
conducted at temperatures in the range of about 180.degree. to 250.degree.
C. and at ambient, or pressures moderately above or below ambient,
pressure. After reaction between the hydroxy groups and methyl phenyl
carbonate is complete or essentially complete, the temperature is
increased to and maintained at about 250.degree. C. up to a maximum of
380.degree. C., preferably 350.degree. C. at ambient and/or reduced
pressures, e.g., final polycondensation pressure in the range of about 0.1
to 100 torr, for a period of time, e.g., 10 to 90 minutes, sufficient to
give either a low molecular weight prepolymer or the high molecular weight
poly(ester-carbonate) product. The prepolymer obtainable at this stage may
be cooled, ground to a suitable particle size and submitted to solid phase
polycondensation at temperatures in the range of about 250.degree. to
300.degree. C. according to known procedures to produce the high molecular
weight poly(ester-carbonate. In some cases, crystallization of the
prepolymer, e.g., from acetone or toluene, may be required prior to solid
phase polycondensation. Some of the prepolymers obtainable according to
our novel process may not be sufficiently crystalline or crystallizable
for use in solid phase polycondensation.
The high molecular weight poly(ester-carbonate) product may be obtained
using melt phase polycondensation wherein the transesterification product
and/or prepolymer is heated at temperatures in the range of about
250.degree. C. up to about 350.degree. C., preferably about 320.degree.
to 350.degree. C., during which the pressure is reduced to about 0.5 torr
or less. Heating under reduced pressure is continued until the high
molecular weight, high melt viscosity poly(ester-carbonate) product is
obtained.
The poly(ester-carbonates) produced in accordance with the process of the
present invention have inherent viscosities of up to about 1.2 dl/g,
usually about 0.3 to 1.0 dl/g, preferably about 0.5 to 0.8, and are useful
in the manufacture of various shaped articles such as molded objects and
extruded films. The inherent viscosities referred to herein are determined
using 0.1 g of poly(ester-carbonate) polymer per 100 mL of a mixture
consisting of 40 weight percent p-chlorophenol, 25 weight percent phenol
and 35 weight percent 1,1,2,2-tetrachloroethane wherein the polymer is
dissolved in the mixture at ambient temperature.
The process provided by the present invention is further illustrated by the
following examples. The films referred to in the examples are prepared
from the poly(ester-carbonates) by compression molding in a Hannafin press
at about 330.degree. to 350.degree. C. for about 30 seconds. Film
toughness is assessed by hand creasing the pressed films.
EXAMPLE 1
A 100-mL, single-necked flask is equipped with a metal stirrer, means for
maintaining a nitrogen atmosphere or a vacuum within the flask and a
molten metal bath which can be raised or lowered to heat the flask or
allow it to cool. The following materials are added to the flask:
______________________________________
17.10 g (0.0750 mole)
2,2-Bis(4-hydroxyphenyl)-
propane
10.19 g (0.0525 mole)
Dimethyl terephthalate
25.08 g (0.1550 mole)
Methyl phenyl carbonate
15.0 mL dry toluene
______________________________________
The flask and contents are heated to distill off the toluene and
azeotropically dry the reactants by slowly immersing the flask in the
molten metal bath (maintained at 200.degree. C.) over a period of about 85
minutes. An n-butanol solution (0.153 mL) of tetraisopropyl titanate
containing 0.032 g Ti per mL (approximately 200 ppm based on the
theoretical yield of polymer) is added to the dried contents of the flask
and the metal bath temperature is immediately increased to 250.degree. C.
for 3 hours. The contents of the flask are continuously stirred under a
nitrogen atmosphere during the heating at 250.degree. C. The metal bath
temperature then is increased to 350.degree. C. and maintained at
350.degree. C. for 30 minutes. The pressure within the flask is decreased
to 0.2 torr over a period of 5 minutes and the polycondensation mixture is
stirred at 350.degree. C. and 0.2 torr for 5 minutes. The
poly(ester-carbonate) product thus obtained exhibits a high melt
viscosity, an inherent viscosity of 0.63 and gives a tough pressed film.
EXAMPLE 2
The following materials are charged to a flask and the toluene is distilled
off to azeotropically dry the reactants according to the procedure
described in Example 1:
______________________________________
17.10 g (0.0750 mole)
2,2-Bis(4-hydroxyphenyl)-
propane
10.19 g (0.0525 mole)
Dimethyl isophthalate
25.08 g (0.1550 mole)
Methyl phenyl carbonate
15.0 mL dry toluene
______________________________________
An n-butanol solution (0.15 mL) of tetraisopropyl titanate containing 0.032
g Ti per mL (approximately 200 ppm based on the theoretical yield of
polymer) is added to the dried contents of the flask and the flask and
contents are heated at 250.degree. C. for 3 hours and then at 330.degree.
C. for 30 minutes. The pressure then is reduced to 0.1 torr over about 10
minutes and the contents of the flask are continuously stirred under a
nitrogen atmosphere 330.degree. C. at 0.1 torr for 2.25 hours. The
poly(ester-carbonate) product thus obtained exhibits a high melt
viscosity, an inherent viscosity of 0.49 and gives a tough pressed film.
EXAMPLE 3
Example 1 is repeated using the following reactants and catalyst:
______________________________________
17.10 g (0.0750 mole)
2,2-Bis(4-hydroxyphenyl)-
propane
9.15 g (0.0375 mole)
Dimethyl 2,6-naphthalene-
dicarboxylate
34.20 g (0.2250 mole)
Methyl phenyl carbonate
200 ppm Ti
______________________________________
and a final polycondensation temperature of 350.degree. C. for 5 minutes.
The poly(ester-carbonate) product thus obtained exhibits a very high melt
viscosity and an inherent viscosity of 0.47.
EXAMPLE 4
The following materials are charged to a flask and the toluene is distilled
off to azeotropically dry the reactants according to the procedure
described in Example 1:
______________________________________
34.20 g (0.150 mole)
2,2-Bis(4-hydroxyphenyl)-
propane
23.28 g (0.120 mole)
Dimethyl terephthalate
50.16 g (0.330 mole)
Methyl phenyl carbonate
25.0 mL dry toluene
______________________________________
An n-butanol solution (0.316 mL) of tetraisopropyl titanate containing
0.032 g Ti per mL (approximately 200 ppm based on the theoretical yield of
polymer) is added to the dried contents of the flask and the flask and
contents are heated at 250.degree. C. for 3 hours and then at 320.degree.
C. for 1.5 hours. The pressure then is reduced to about 0.5 torr over
about 15 minutes and the polycondensation is continued for 10 minutes. The
resulting low melt viscosity prepolymer is cooled and ground through a 3
mm screen in a Wiley mill. The ground prepolymer has an inherent viscosity
of 0.25 and is crystallized by slurrying with acetone overnight, filtering
and vacuum drying at 100.degree. C. The crystallized prepolymer is further
polycondensed in the solid phase by heating at 0.1 torr at 120.degree. C.
for 2 hours, at 200.degree. C. for 30 minutes, at 275.degree. C. for 30
minutes and at 290.degree. C. for 4 hours. The poly(ester-carbonate)
product thus obtained exhibits an inherent viscosity of 1.17 and gives a
very tough pressed film.
EXAMPLE 5
Example 1 is repeated using the following reactants and catalyst:
______________________________________
6.84 g (0.030 mole)
2,2-Bis(4-hydroxyphenyl)-
propane
10.64 g (0.070 mole)
Methyl 4-hydroxybenzoate
21.74 g (0.143 mole)
Methyl phenyl carbonate
200 ppm Ti
______________________________________
and a final polycondensation temperature of 330.degree. C. for 15 minutes.
The poly(ester-carbonate) product thus obtained exhibits a very high melt
viscosity, an inherent viscosity of 0.59 and gives a tough pressed film.
EXAMPLE 6
The following materials are charged to a flask and the toluene is distilled
off to azeotropically dry the reactants according to the procedure
described in Example 1:
______________________________________
10.64 g (0.070 mole)
Methyl 4-hydroxybenzoate-
3.63 g (0.033 mole)
Hydroquinone
21.71 g (0.1426 mole)
Methyl phenyl carbonate
20.0 mL dry toluene
______________________________________
An n-butanol solution (0.078 mL) of tetraisopropyl titanate containing
0.032 g Ti per mL (approximately 200 ppm based on the theoretical yield of
polymer) is added to the dried contents of the flask and the flask and
contents are heated at 200.degree. C. for 2 hours, at 250.degree. C. for 3
hours and then at 330.degree. C. for 30 minutes. The pressure then is
reduced to 0.1 torr over about 10 minutes and the contents of the flask
are continuously stirred under a nitrogen atmosphere at 330.degree. C. at
0.1 torr for 1 hour. The poly(ester-carbonate) product thus obtained
exhibits a high melt viscosity, an inherent viscosity of 0.77 and gives a
tough pressed film.
EXAMPLE 7
The following materials are charged to a flask and the toluene is distilled
off to azeotropically dry the reactants according to the procedure
described in Example 1:
______________________________________
10.64 g (0.070 mole)
Methyl 4-hydroxybenzoate-
5.58 g (0.030 mole)
4,4'-Biphenol
20.75 g (0.1365 mole)
Methyl phenyl carbonate
15.0 mL dry toluene
______________________________________
Tetraisopropyl titanate containing (0.0355 g; (approximately 400 ppm Ti
based on the theoretical yield of polymer) is added to the dried contents
of the flask and the flask and contents are heated at 250.degree. C. for
3.25 hours and then at 330.degree. C. for 1.25 hours. The pressure then is
reduced to 0.3 torr over about 10 minutes and the contents of the flask
are continuously stirred under a nitrogen atmosphere at 330.degree. C. at
0.3 torr for 3 hours. The poly(ester-carbonate) product thus obtained
gives a tough pressed film and exhibits low solubility in the solvent
mixture used to determine inherent viscosity.
The invention has been described in detail with particular reference to
preferred embodiments thereof, but it will be understood that variations
and modifications can be effected within the scope and spirit of the
invention.
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